condition mean min max ZT0-3 8.5032675 7.41332 9.593215 ZT4-7 9.63909 9.63909 9.63909 ZT8-11 7.39634 7.39634 7.39634 ZT12-15 0 0 0 ZT16-19 8.1247 8.1247 8.1247 ZT20-23 8.737415 8.737415 8.737415